Calcium plays one of the central roles in the signal transduction, and further it is an important structural element in biological systems. From protozoa to vertebrata, deposited calcium salts helps to keep rigid bodily shapes of animals, calcium phosphate being the main component of endoskeletons in the vertebrates and calcium carbonate of exoskeletons in the invertebrates. Calcified exoskeletons with calcium carbonate minerals as the main constituents are widespread among echinoderms, mollusks, and arthropods, providing protection and serving as calcium storage. Some crustaceans store calcium carbonate temporarily, in an amorphous state, which makes it better available, particularly for quick mobilization during the mineralization of their new exoskeleton structures after molting. In freshwater crayfish, the calcium carbonate deposits comprise a pair of disc-like structures, known as gastroliths, that are located on each side of the stomach wall. Gastrolith formation takes place in the gastrolith pouch, a cavity formed between the columnar epithelium of the gastrolith disc and the cardiac stomach wall. The main functions of the gastrolith disc epithelium are the transport of hemolymph calcium to the gastrolith and the synthesis of the gastrolith organic matrix. The formation of amorphous calcium carbonate in the living bodies of, for example, crayfish is rather intriguing, since amorphous minerals are usually thermodynamically unstable. Amorphous calcium carbonate (ACC) tends to transform to its crystalline polymorphs, mainly calcite and aragonite, WO 2005/11541.4 employs crustacean organs for providing compositions with stable ACC which is readily available for human consumption. In view of the general metabolic and biomechanical importance of calcium, and since ACC is a potentially more soluble and absorbable form of calcium carbonate as a dietary supplements, it is an object of the invention to provide new methods for preparing amorphous calcium carbonate.
It is another object of this invention to provide pharmaceutical and nutraceutical compositions comprising stable ACC.
Other objects and advantages of present invention will appear as description proceeds.